Agro-forestry residues represent a vast reservoir of renewable matter and energy and have played a pivotal role in human development. However, with shifts in production modes and lifestyles, this biomass has begun to exhibit seasonal and regional surpluses. Improper disposal of agro-forestry residues leads to environmental burdens and greenhouse gas emissions. Biomanufacturing, represented by microbial fermentation, offers a sustainable solution to valorize these residues into high-value products.

This Special Issue (SI) of Systems Microbiology and Biomanufacturing focuses on "Biomanufacturing from Agro-forestry Residues" for the development of advanced bioprocesses to produce high-quality feed, fertilizers, bioenergy, and bioactive ingredients. The SI covers agricultural and environmental microbiology, biotechnology, and bioprocess engineering for the green valorization of agro-forestry residues. Specific topics include, but are not limited to, the processes and molecular mechanisms of aerobic fermentation, anaerobic digestion, and insect-mediated bioconversion, especially those integrating artificial intelligence, systems biology, or carbon emission analysis.

Algae, including microalgae and macroalgae, are increasingly recognized as sustainable biological platforms to produce chemicals, food ingredients, and functional materials. Their photosynthetic efficiency, rapid growth, and capacity to utilize CO₂ and diverse nutrient sources make them attractive cell factories within green biotechnology and circular bioeconomy frameworks. Recent advances in metabolic engineering, synthetic biology, and systems-level analysis have significantly expanded the scope of algal biotechnological applications.

This Special Issue aims to highlight recent progress and emerging strategies in algal genetic and metabolic engineering to produce chemicals, fuels, food, feed and materials, covering fundamental insights through applied bioprocess development, specifically focused on application of AI and ML. It seeks to bring together interdisciplinary contributions that advance the understanding, engineering, and industrial translation of algal systems.

Specific topics include studies on algal metabolism, photosynthetic carbon fixation, and systems biology approaches enabling rational pathway design and optimization. Research on genetic and metabolic engineering tools, such as genome editing, synthetic regulatory elements, and nuclear or chloroplast pathway engineering is strongly encouraged. Contributions focusing on the engineered production of bio-based chemicals, specialty metabolites, nutraceuticals, food and feed components, lipids, pigments, polysaccharides, and biopolymer precursors are within scope. It also focuses on algal-derived materials and biomaterials, stress-based and adaptive metabolic engineering strategies, and bioprocess engineering challenges including strain robustness, photobioreactor design, scale-up, and downstream processing. Studies integrating algal platforms with CO₂ capture, waste valorization, life cycle assessment, techno-economic analysis, and circular bioeconomy concepts are particularly encouraged.

Both original research articles and critical reviews are welcome.